It is known to provide vacuum packaging apparatus having one or two vacuum chambers to which differential pressures are used for the purpose of evacuating and hermetrically sealing a package. Examples of this type of apparatus are described in U.S. Pat. Nos. 3,491,504 (Young), 3,835,618 (W. R. Grace), and 4,480,425 (Furukawa).
The present invention has particular relevance to tray (as opposed to trayless or bag packaging systems) where articles to be packed are first placed in a tray or trays in a vacuum chamber, the chamber and packages evacuated, a film is applied to the tray or trays and the vacuum chamber pressures are raised so that the heated film adheres to the tray or trays and/or product in the tray.
Where a number of trays are to be filled, a pallet of the trays is first placed in a magazine, they are then filled with product and then placed in the vacuum chamber where the packages are evacuated and the film applied over the top of the trays. When the trays leave the vacuum chamber they are cut into individual packages by cutting apparatus.
The cutting or slitting of the trays from the magazine into individual elements is an operation presently achieved manually or by a separate machine.